Ecological Strategy for Eutrophication Control

Abstract

Water monitoring results of the Danjiangkou Reservoir indicated that total nitrogen and total phosphorus concentrations are high and therefore worse than required for central drinking water supplies. Nutrients including nitrogen and phosphorus accumulated in the bank cultivated land were greater than those contained within the river estuary sediment as well as in the reservoir bay sediment. This implies that high concentrations of loosely exchangeable phosphorus (166.53 mg/kg) in cultivated land could, after the completion of the dam heightening project, easily lead to the development of algal blooms. Serious water and soil loss occurring in the reservoir area will promote the transportation of non-point source pollution mainly caused by untreated agricultural domestic wastewater, chemical fertilizer and livestock farming, which accounted for more than 50% of the total basin's nutrient input loads. Ecological control techniques were therefore the first choice for nutrient reduction and water quality guarantee in the Danjiangkou Reservoir. In order to guide the ecological restoration process, leading international ecological methodologies were summarized and compared, taking into consideration aspects of engineering, as well as ecological, biological, environmental and economic advantages and disadvantages. Finally, novel ecological filtration and a purification dam were designed for eutrophication control.

Assessing ways to combat eutrophication in a Chinese drinking water reservoir using SWAT

“…Based on watershed models as that applied in the present study, such tools may also allow spatial differentiation of crop-specific fertilizer norms, which is common in several Western countries (Kronvang et al 2008). Awareness of spatial vulnerability may improve the layout and selection of areas for implementation of measures such as ditches and wetlands (Jiang et al 2007) that locally lower agricultural non-point source nutrient exports -as called for by Tang et al (2012). Thus, control of agricultural intensity according to vulnerability of the land may preserve the overall yields at watershed scale, while lowering nutrient losses and thereby better balancing food security and the quality of the water supply.…”

Assessment of typical natural processes and human activities’ impact on the quality of drinking water

“…Water and sediment investigation results indicate that organic matters transported from the urban tributaries and accumulations in the cultivated lands are the most significant source of pollution and cause continuous water quality deterioration. Moreover, serious water and soil loss and a shortage of ecological barrier constructions encourage the transportation of rural nonpoint source pollutants from livestock farming and chemical fertilizer application, which contributed over half of the total organic matter input loads (Tang et al 2012).…”

Biochar from Alternanthera philoxeroides could remove Pb(II) efficiently

“…As one of the high-level nutrient adapted hydrophytes, Alternanthera philoxeroides, also known as alligator weed, have been widely used in the ecological restoration of eutrophic lakes (Tang et al, 2011). However, the harvest of hydrophytes brings problems for treatment, especially due to its large amount (Xiao et al, 2009).…”